Device for reducing TOC (total organic carbon) in ultrapure water

Abstract

In order to reduce TOC by UV radiation, in the ultrapure water production process, a cylindrical UV reactor surrounded by a quartz sleeve, the annular water flow channel width of which does not exceed 10 mm to 15 mm, is provided. This results in a high exposure of water to UV radiation at a wavelength of 185 nm, as well as all other wavelengths of less than 200 nm, within the annular region. In order to optimize the mixing of water within the region, baffles or perturbators are provided at multiple locations to achieve mixing of different layers of liquids, thereby promoting radial movement of water around the quartz tube.

Description

TECHNICAL FIELD

[0001] The present invention relates to water treatment, and in particular to a treatment method using ultraviolet (UV) radiation to obtain ultrapure water. BACKGROUND

[0002] In the field of water treatment, including the production of ultrapure water, a UV wavelength of 185 nm is often used to reduce the total organic carbon (TOC) in the water. However, this UV wavelength is very easily absorbed in water, and it is believed that at a distance of more than 10 mm from the UV source, the 185 nm wavelength and all other wavelengths below 200 nm are almost completely absorbed by water. Typically, low-pressure mercury lamps emit a spectrum of 254 nm and 185 nm.

[0003] Conventional designs of UV reactors do not limit the distance of the UV sources to the outer wall of the chamber to more than 10 mm. In some cases, the reactor comprises a large cylindrical body in which a plurality of elongated UV lamp tubes are arranged axially. In such a cylindrical tube, the water is circulated around the lamp tubes. Despite this, the maximum propagation distance of the UV in the water often exceeds 10 mm.

[0004] The prior art has recognized that when water flows through a UV reactor, if one or more UV sources are arranged axially, it is necessary to use baffles or disruptors to break the laminar flow. Examples of this can be found in US patents 5,352,359, 5,846,437, US publications 2011 / 0318237 and 2011 / 0024365, and UK patent file GB 2579966. See also Applicant US patent 12,077,456. These patents and publications show various types of baffles and devices for inducing vortices and mixing in ultraviolet water disinfection reactors. SUMMARY

[0005] An improved and more efficient UV reactor for treating water, particularly for reducing TOC and producing ultrapure water. The reactor employs a cylindrical configuration with axial flow of water between an internal UV-emitting device and the cylindrical wall. The radial propagation distance of the UV radiation, particularly at 185 nm wavelength, is preferably no more than about 10 mm to ensure complete UV treatment of the water. The cylindrical housing of the reactor is preferably made of polished stainless steel to provide relatively high reflectivity. A central elongated UV lamp is surrounded by a quartz sleeve, and the water, which flows generally axially through the reactor, circulates along the UV lamp and quartz sleeve and its surroundings. In a preferred embodiment, the annular cross-sectional width of the passageway for the water is no more than about 10 mm. Thus, the water is highly exposed to the 185 nm wavelength UV light as it circulates within the reactor region.

[0006] The annular flow path of the water includes baffles or turbulators, the geometry of which is an important aspect of the invention. The one or more baffles or turbulators are preferably planar structures extending inwardly from the reactor housing wall, blocking a substantial portion of the annular passageway and establishing a flow pattern that is left / right and top / bottom symmetric, but not symmetric in both directions, i.e., the flow openings on the left side are different from the flow openings on the right side, and the flow openings on the top side are different from the flow openings on the bottom side. The geometry of the turbulators creates vortices that facilitate movement between different radial layers of the water, without creating significant pressure losses in the reactor. This results in as many TOC molecules in the water as possible being exposed to the proximity of the quartz sleeve and reacting with the OH radicals produced by photolysis.

[0007] In one embodiment, the invention provides a device for reducing TOC in ultrapure water by UV oxidation in the production of ultrapure water, the device comprising:

[0008] an elongated stainless steel cylindrical tube,

[0009] an elongated high-purity quartz tube within the stainless steel cylindrical tube defining an annular channel volume between the quartz tube and the stainless steel cylindrical tube having a width no greater than about 10 mm,

[0010] a UV source within the quartz tube positioned to emit UV radiation outwardly through the annular channel volume, the radiation including wavelengths less than 200 nm, and

[0011] a water inlet at one end of the elongated stainless steel cylindrical tube and a water outlet at the other end, whereby water can be directed from the one end through the annular channel volume to the other end to oxidize and / or reduce TOC in the water.

[0012] In one embodiment, the device comprises at least one baffle within the annular channel-like volume and in the path of water flowing through the annular channel-like volume that causes exchange between the inner and outer layers of the water as it flows through the annular channel-like volume, such that substantially all of the water flowing through is exposed adjacent to the quartz tube and the UV source.

[0013] In one embodiment, the baffles are configured to disturb the laminar flow of the water by creating eddies and vortices in the flowing water.

[0014] In one embodiment, the device comprises a series of the baffles within the annular channel-like volume.

[0015] In one embodiment, each baffle has a preferential primary flow opening in a particular rotational direction, and wherein the series of baffles are staggered in rotational direction from one baffle to another, such that the water is directed to further mix and swirl as it flows through the annular channel-like volume, causing substantially all of the water to flow adjacent to the quartz tube.

[0016] In one embodiment, the present invention provides a series of elongated stainless steel cylindrical tubes with quartz tubes and UV sources in a modular ultrapure water production device, wherein each of the water inlets and outlets comprises a manifold plate that connects the water inlets or outlets to all of the stainless steel cylindrical tubes to produce high throughput of ultrapure water.

[0017] In one embodiment of the present invention, the annular channel width through the tubes can be up to 15 mm, which when combined with baffles or disturbers, can effectively direct the water to move vigorously in and out of the channel to maximize the exposure of the water to the UV radiation.

[0018] In a preferred embodiment, the length of the reactor comprises multiple disturbers, but the geometry of the disturbers is rotated in sequence.

[0019] In one embodiment, the present invention provides a device for reducing TOC in ultrapure water by UV oxidation in ultrapure water production, the device comprising:

[0020] an elongated stainless steel cylindrical tube,

[0021] an elongated high purity quartz tube within the stainless steel cylindrical tube that defines an annular channel-like volume between the quartz tube and the stainless steel cylindrical tube having a width of no more than about 15 mm,

[0022] a UV source within the quartz tube positioned to emit UV radiation outwardly through the annular channel-like volume, the radiation comprising wavelengths less than 200 nm,

[0023] a water inlet at one end of the elongated stainless steel cylindrical tube and a water outlet at the other end, whereby water can be directed from the one end through the annular channel-like volume to the other end to oxidize and / or reduce TOC in the water, and

[0024] at least one baffle within the annular channel-like volume and in the path of water flowing through the annular channel-like volume effective to cause exchange between inner and outer layers of the water as the water flows through the annular channel-like volume, whereby substantially all of the water flowing through is exposed adjacent to the quartz tube and the UV source.

[0025] In one embodiment, the baffles are configured to disturb laminar flow of the water by creating eddies and vortices in the flowing water.

[0026] In one embodiment, a series of the baffles are included within the annular channel-like volume.

[0027] In one embodiment, each baffle has a preferential primary flow opening in a particular rotational direction, and wherein the series of baffles are staggered in rotational direction from one baffle to another, whereby the water is directed to further mix and swirl as it flows through the annular channel-like volume, causing substantially all of the water to flow adjacent to the quartz tube.

[0028] In one embodiment, the present invention provides a series of elongated stainless steel cylindrical tubes with quartz tubes and UV sources in a modular ultrapure water production device, wherein each of the water inlets and the water outlets include a manifold plate connecting the water inlets or the water outlets to all of the stainless steel cylindrical tubes to produce high production volumes of ultrapure water.

[0029] The disruptors in the UV reactors of the present invention can be limited to flow channels of about 10 mm wide to optimize flow disruption and thereby increase the UV dose per water molecule. Tests show that the specific energy requirements for this design can be reduced by a factor of 1.5 compared to existing conventional configurations. In addition, the present invention typically uses fewer UV lamps and less footprint, which can be reduced to 1 / 3 of existing configurations.

[0030] Other embodiments of the present invention can employ multiple UV lamp tubes, where the depth of penetration of UV radiation in the water does not exceed 10 mm (or 15 mm with appropriate baffling). BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a perspective view showing a UV water purification reactor of the present invention.

[0032] Figure 2is a cross-sectional perspective view showing the reactor.

[0033] Figure 3 is a side cross-sectional view of the reactor, with the length shortened.

[0034] Figure 4 and Figure 5 are schematic cross-sectional views taken along planes 4-4 and 5-5 in Figure 3 showing the position of the baffle or disrupter inside the reactor structure.

[0035] Figure 6 is an enlarged view showing one baffle example.

[0036] Figure 7 is a perspective view showing the operable baffle configuration.

[0037] Figure 8 is a perspective view showing the baffle in Figure 6

[0038] Figure 9 is a cross-sectional view taken along plane 8-8 in Figure 6 showing the baffle.

[0039] Figure 10 is a perspective schematic view showing the position of one of the baffles in a tubular reactor.

[0040] Figure 11 is a perspective schematic view showing the turbulent mixing flow induced by the baffles inside the reactor tube.

[0041] Figure 12 is a perspective schematic view showing the turbulence induced by two consecutive baffles with a 90° difference in direction inside the reactor tube.

[0042] Figure 13 and Figure 14 are perspective views showing other embodiments of the reactor tube with multiple UV lamp assemblies.

[0043] Figure 15 and Figure 16 are cross-sectional elevation views showing the structure preventing the escape of UV radiation from the water inlet and outlet. DETAILED DESCRIPTION

[0044] Figure 1 ​An embodiment of an ultrapure water treatment UV reactor 10 is shown for removing TOC from water. The water inlet and outlet are indicated as 12 and 14, respectively. As shown, the tube is elongated, for example, in one embodiment, the overall length can be about 1.7 m and the outer diameter can be about 7 cm. This is only one example, other dimensions can be used. A series of internal baffles 16 are indicated within the reactor tube 18.

[0045] Figure 2 A cross-sectional view of the reactor tube 18 is shown, which contains a UV lamp 20, preferably located at the center of an elongated quartz sleeve 22. The sleeve 22 is preferably made of high purity quartz (synthetic quartz). The interior of the sleeve 22 is sealed to prevent liquid from entering. The water to be treated flows through an annular channel 24 between the outside of the quartz sleeve 22 and the inside of the cylindrical housing 18, which is preferably polished stainless steel. The maximum absolute width of the annular channel 24 is 10 mm to ensure that every water molecule and its contaminants are exposed to UV radiation (preferably at a wavelength of 185 nm).

[0046] Figure 3 Some construction details of the preferred embodiment of the reactor are shown. For clarity, the length of the reactor tube 18 is shortened in the figure, as indicated by the dashed line 26.

[0047] As mentioned previously, the length and diameter of the tube can vary. Although the wall thickness of the tube 18 can be about 2 mm (± 0.2 mm), this thickness can also vary.

[0048] As can be seen from the figure, the baffles 16 are preferably spaced apart within the interior of the tube 18. Figure 3 Five baffles are shown by way of example. Another structure 28 is also indicated in the figure, but the function of the structure is only to hold the quartz sleeve 22 at the center of the cylindrical tube 18.

[0049] Figure 6 、 Figure 7 、 Figure 8 and Figure 9An exemplary embodiment of a baffle 16 is shown. In this preferred geometry, the baffle comprises a short sleeve 30 of the same outer diameter as the tube 18, welded into the steel tube 18 at the discontinuity, as shown. The baffle structure is shown as 32. In this particular geometry, the baffle structure is symmetric about a vertical plane, but the geometry of the top and bottom is different from the geometry of the left and right sides, as shown. The baffle of this embodiment has an inside convex curve (preferably an arc) 32a at the top and bottom, while at the left and right sides, the baffle has an inside concave curve as 32b, both sides being so configured to fit over the quartz sleeve 22. These shapes can be arcs, with a radius of about 22 mm for arc 32a and a radius of about 23 mm for arc 32b, to ensure a small gap from the outer diameter of the quartz tube, allowing for mechanical assembly. In this example, the overall outer diameter of the baffle is about 70 mm, the same as the tube itself. The inner diameter of the tube can be about 66 mm. The thickness of the sleeve 30 can be about 2 mm, and the thickness of the baffle 32 can also be about 2 mm.

[0050] Figure 7 Only the operable portion of the baffle structure is shown, which is in the annular channel in the path of the water flow, without showing the tubular sleeve 30 (as shown in Figure 6 , Figure 8 and Figure 9 ).

[0051] Figure 4 and Figure 5 show that when multiple baffles are included, the orientation of adjacent baffles alternates, preferably by 90°. Thus, Figure 4 shows the orientation of the baffle 16 as Figure 6 , while Figure 5 shows the baffle rotated by 90°. Similarly, the orientation of the baffles alternates along the length of the tube 18. As shown in Figure 6 , there is little water flow on the left and right sides between the baffle and the quartz tube 22. However, at the top and bottom, the shape of the flow opening 40 is as shown, comprising two large areas connected by a narrow constriction, with a minimum gap of about 1 to 2 mm. All baffles are deburred, without any sharp edges, to create the turbulence required in the water passing through the tube 18.

[0052] Figure 10 The baffles 16 within the tube 18 are shown in perspective, surrounding the quartz sleeve 22. Figure 11 The turbulence of the water flow through a single baffle 16 is shown in schematic fashion, with the primary flow area of the baffle on the left and right sides. In this perspective, the water flow is from left to right, with the flow lines showing the turbulence and eddies, indicated by the lines 36 with arrows.

[0053] A plurality of spaced apart and staggered rotationally arranged baffles (as shown in Figure 4 and Figure 5 ) are provided along the length of the annular channel, which can induce flow channeling and streaming within the volume. In addition, as shown in Figure 11 , eddies and vortices are generated within the annular flow channel volume, which help to facilitate flow between different radial layers of water without significant pressure loss.

[0054] Figure 12 The effect of a plurality of baffles in series within the tube (i.e. within the annular flow channel volume) is shown generally and schematically. Upstream baffle 16a is shown with its primary open area on the left and right, causing the primary water flow to be concentrated in two symmetric dark flow channel areas. This results in a spiraling or helical motion of the water flow, as well as vortices. This effect is enhanced as the water flow reaches the second baffle 16b. The baffle 16b is rotated 90° from the first baffle, causing the primary water flow to spiral and further generate vortices and eddies, causing the water to flow outwardly and then inwardly, ensuring that all water is exposed to the UV source (i.e. the quartz tube) during its flow.

[0055] Note that the baffles can have other forms and have different flow channel configurations, as long as the baffle configuration induces rotation, eddies and vortices in the water flow as it passes through the tube. The baffles are preferably staggered in their rotational orientation, with the primary flow opening of each baffle oriented 180° apart (or asymmetrically in the up-down and left-right directions). However, other baffle configurations are possible, such as non-planar baffles with grooves or vanes that cause the water to flow outwardly and inwardly for optimal UV exposure. The annular channel width within the tube is preferably about 10 mm (±10%), but can be as wide as 15 mm if sufficient mixing is provided by the baffles to ensure that all water is exposed to the quartz tube at some point in time.

[0056] Figure 13 and Figure 14 show other configurations of the reactor of the present application. Figure 13 A set of six tubes is shown in Fig. 6, each with its own annular channel volume, fed by a single inlet 12 and a single outlet (not shown). Manifold plates 38 at each end connect all the tubes to the inlet and outlet. Figure 14 Nineteen tubes are shown in Fig. 7, again fed by a single inlet 12 and a single outlet, but with each tube having an independent inlet channel volume through the inlet and outlet end manifold plates 39.

[0057] The reactor of the present application is preferably constructed to prevent UV radiation from entering directly and passing through the outlet 14 and inlet 12 (not shown) of the reactor. Figure 15 and Figure 16 show two different structural configurations to prevent this. InFigure 15 In the case of FIG. 1, the position of the UV lamp 20 is such that its end 41 does not reach the water outlet position (at the right side) and therefore the UV radiation emitted radially does not pass directly through the water outlet (or the water inlet). In the case of FIG. 2, the position of the UV lamp 20 is such that its end 41 reaches the water outlet position (at the right side) and therefore the UV radiation emitted radially does pass directly through the water outlet (or the water inlet). Figure 15 In the case of FIG. 1, the position of the UV lamp 20 is such that its end 41 does not reach the water outlet position (at the right side) and therefore the UV radiation emitted radially does not pass directly through the water outlet (or the water inlet). In the case of FIG. 2, the position of the UV lamp 20 is such that its end 41 reaches the water outlet position (at the right side) and therefore the UV radiation emitted radially does pass directly through the water outlet (or the water inlet). Figure 16 In the case of FIG. 1, the position of the UV lamp 20 is such that its end 41 does not reach the water outlet position (at the right side) and therefore the UV radiation emitted radially does not pass directly through the water outlet (or the water inlet). In the case of FIG. 2, the position of the UV lamp 20 is such that its end 41 reaches the water outlet position (at the right side) and therefore the UV radiation emitted radially does pass directly through the water outlet (or the water inlet).

[0058] In the present description, the use of the terms "about" or "approximately" in the description of numerical ranges means the inclusion of the values within 10% of the stated value.

[0059] The above preferred embodiments are intended to be illustrative of the principles of the present application, and not limiting thereof. Various other embodiments and changes can be apparent to those skilled

Claims

1. A device for reducing TOC in ultrapure water, applied in ultrapure water production, which reduces TOC in ultrapure water through UV oxidation, characterized in that, The device includes: A long, rectangular stainless steel cylindrical tube. An elongated high-purity quartz tube located inside the stainless steel cylindrical tube defines an annular channel-like volume with a width not exceeding approximately 10 mm between the quartz tube and the stainless steel cylindrical tube. A UV source located within the quartz tube is positioned to emit UV radiation outward through the annular channel-like volume, the radiation comprising wavelengths less than 200 nm. The elongated stainless steel cylindrical tube has an inlet at one end and an outlet at the other end, allowing water to be guided from one end through the annular channel-like volume to the other end, thereby oxidizing and / or reducing the TOC in the water.

2. The apparatus for reducing TOC in ultrapure water as described in claim 1, characterized in that, The device includes at least one baffle within the annular channel volume and in the path of water flowing through the annular channel volume, causing an exchange between the inner and outer layers of the water as the water flows through the annular channel volume, so that the flowing water is substantially entirely exposed to the vicinity of the quartz tube and the UV source.

3. The apparatus for reducing TOC in ultrapure water as described in claim 2, characterized in that, The baffle is configured to disturb the laminar flow of water by creating eddies and vortices in the flowing water.

4. The apparatus for reducing TOC in ultrapure water as described in claim 3, characterized in that, The device comprises a series of baffles within the annular channel-shaped volume.

5. The apparatus for reducing TOC in ultrapure water as described in claim 4, characterized in that, Each baffle has a preferred main flow opening in a specific direction of rotation, and the series of baffles are staggered from one baffle to another in the direction of rotation, so that when water flows through the annular channel volume, the water is guided to be further mixed and swirled, resulting in virtually all of the water flowing to the adjacent quartz tube.

6. A series of elongated stainless steel cylindrical tubes with a quartz tube and a UV source as described in claim 1, characterized in that, in a modular ultrapure water production device, Each of the inlets and outlets includes a manifold that connects the inlet or outlet to all of the stainless steel cylindrical tubes to produce high-volume ultrapure water.

7. A device for reducing TOC in ultrapure water, applied in ultrapure water production, wherein the TOC in ultrapure water is reduced by UV oxidation, characterized in that... The device includes: A long, rectangular stainless steel cylindrical tube. An elongated high-purity quartz tube located inside the stainless steel cylindrical tube defines an annular channel-like volume with a width not exceeding approximately 15 mm between the quartz tube and the stainless steel cylindrical tube. A UV source located within the quartz tube is positioned to emit UV radiation outward through the annular channel-like volume, the radiation comprising wavelengths less than 200 nm. The elongated stainless steel cylindrical tube has an inlet at one end and an outlet at the other, allowing water to be guided from one end through the annular channel to the other end to oxidize and / or reduce the TOC in the water. It includes at least one baffle within the annular channel volume and in the path of water flowing through the annular channel volume, which effectively causes exchange between the inner and outer layers of the water as the water flows through the annular channel volume, thereby exposing substantially all of the flowing water to the vicinity of the quartz tube and the UV source.

8. The apparatus for reducing TOC in ultrapure water as described in claim 7, characterized in that, The baffle is configured to disturb the laminar flow of water by creating eddies and vortices in the flowing water.

9. The apparatus for reducing TOC in ultrapure water as described in claim 8, characterized in that, A series of baffles contained within the annular channel-shaped volume.

10. The apparatus for reducing TOC in ultrapure water as described in claim 9, characterized in that, Each baffle has a preferred main flow opening in a specific direction of rotation, and the series of baffles are staggered from one baffle to another in the direction of rotation, so that when water flows through the annular channel volume, the water is guided to be further mixed and swirled, resulting in virtually all of the water flowing to the adjacent quartz tube.

11. A series of elongated stainless steel cylindrical tubes with a quartz tube and a UV source as described in claim 7, characterized in that, in a modular ultrapure water production device, Each of the inlets and outlets includes a manifold that connects the inlet or outlet to all of the stainless steel cylindrical tubes to produce high-volume ultrapure water.

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